Means for controlling gunfire



1940- F. R. CHAMBERLAIM'JR 2,186,007

MEANS FOR CONTROLLING GUNFIRE Filed Feb; 7, 1959 2 Sheets-Sheet 1 lnvan L m P- J11 FI'P'E' Elev-1'; R [1111 h vlnin, y gg x W44 At 1'. U 11 EV5 Patented Jan. 9, 1940 2,186,007 MEANS FOR CONTROLLING GUNFIRE Frederick R. Chamberlain, Jr.,

Fortress Monroe, Va.

Application February 7, 1939, Serial No. 255,072

7 Claims. (Cl. 33-66) (Granted under the act of March 3, 1883, as amended April 30, 1928; 370 0. G. 757) The invention described herein may be manufactured and used by or for the Government for governmental purposes, without the payment to me of any royalty thereon.

This invention relates to means for controlling gunfire, and more particularly to methods and means of improving continuosuly pointed fire on moving aerial targets based on observations made from points or stations located relatively remote from the position of the gun or guns, and correlated in conformity with certain principles hereinafter set forth.

A commonplace practice in the prior art, where adjustment of gunfire has been made by rendering the trajectory visible through the use of tracer ammunition, has been to adjust in such manner as to make the trajectory appear to pass through the target by changing the gun pointing in appropriate direction. However, in the employment of this method of fire adjustment certain undesirable shortcomings have been recognized owing to the visual illusion presented by the deficiency of stereoscopic sense, or ability to perceive an object relative to another in range or depth relation, existing in the binocular vision of the normal human being; and hence the inability of a normal observer to accurately determine the relation between a tracer path and target, at ranges of a depth exceeding relatively short distances.

Asthe data available from a true determination of the existing relation between a line or path of fire made visible by tracer ammunition and a moving aerial target afiords a basis for precise and substantially instantaneous adjustments of fire, many attempts have heretofore been made to devise a fire control system operable in a manner that would eliminate the above mentioned visual illusion; but so far as I am aware all of these attempts have been unsuccessful or of indifferent success because of failure to omit the requirement of observations dependent for their accuracy upon the stereoscopic sense of the observer in one degree or another;

It is an object of this invention to disclose certain principles regarding the observation of a target relative to a line or path of gunfire made visible by tracer ammunition which renders it possible to employ a fire control system operable independently of the stereoscopic sense of the observers used in thesystern, and to disclose certain apparatus whereby a practical adaptation of the principles involved may be embodied in the system.

With the foregoing and other objects in view,

the invention resides in the novel disposition of the-observing stations used in the fire control system disclosed and combination of apparatus employed, hereinafter described and claimed, it being understood that changes in the precise embodiment of the invention herein disclosed may be made within the scope of what is claimed without departing from the spirit of the invention.

A present preferred embodiment of the invention is illustrated in the accompanying drawings wherein- Figure l is a horizontal projection of a typical apparent trajectory and intersecting lines of sight originating at lateral or flank observing stations,

Fig. 2 is a vertical projection of a typical apparent trajectory and intersecting lines of sight originating at observing stations displaced forwardly and rearwardly of the gun position.

Fig. 3 is a schematic layout of observing stations correlated in accordance with this invention and disposed to cover a field of fire 360 in azimuth.

Fig. 4 is a diagrammatic layout of one embodiment of apparatus for receiving observed data and selectively transmitting a part of the received data to the sight of a gun or guns.

To facilitate this description the term apparent trajectory will be referred to simply as trajectory and for the purpose of this description is defined asa curved line determined by the positions of a succession of tracers, at a given instant.

Referring now to the drawings by character of reference and wherein the same characters identify the same elements throughout the views, and more particularly to Fig. 1; the horizontal projection of a trajectory H emanating from gun G is shown as it would appear in this projection plane when firing tracer ammunition at a moving aerial target '1 having a direction of flight indicated by arrow A. Located on either flank or laterally of the gun position are observing stations from which vertical deviations of the trajectory from the target maybe observed and utilized to adjust fire. The observing station on the left flank, as viewed in Fig. 1, is designated O1 and the observing station on the right flank as 02. Several rays identified by character S1 indicating lines of sight emanating from observing station 01, on the side of the trajectory H, which for convenience oi identification I term the convex side of the trajectory, are shown intersectingthe trajectory H. The lines of sight S1 the trajectory H at two points.

are merely typical of an infinite number of similar lines of sight that might be shown as extending from station 01 in intersecting relation With trajectory H, and illustrate that many of the lines of sight $1 from. station 01 intersect It is at once discernible, when disclosed, that a target T as viewed from station 01 may appear to the observer to be in any one of numerous positions on any one of the lines of sight S1 due to the visual illusion effected by the inability of the observer to properly visualize the true existing relation of depth or distance between the target and that portion of the trajectory involved. This illusion is particularly noticeable within the angular limits of those rays or lines of sight which intersect the trajectory twice, for within this intercept of the trajectory a true visualization of the position of the target in range must be had in relation to the trajectory intercept in range before the actual line of sight passing through the target can be determined. It is of course obvious that if the true line of sight passing through the target cannot be ascertained that it is impossible to determine the true deviation of the target from the trajectory.

From the opposed flank or lateral observing station 02 rays S2 representing lines of sight, are shown extending in intersecting relation with the trajectory H. An examination of the rays S2 will disclose that the lines of sight represented thereby intersect the trajectory H at one and only one point. It will also be noted that the observing station 02 is on the concave side of the trajectory which discloses the principle that lines of sight originating from a point on the concave side of the trajectory can only intersect the trajectory at one point. Since an observer at station 02 is not required to visualize thre target T in its true position of range relative to the trajectory H before the true line of sight S2 passing through the target can be determined it is a comparatively simple matter to determine the position of the trajectory relative to the target, as such determination is. made independent of the stereoscopic sense of the observer. In other words the line of sight S2 passing through the target from a point on the concave side of the trajectory is always determined without regard to distance between the target and trajectory.

Now referring to Fig 2 wherein the position of the gun or guns is again designated by the character G, there is shown the projection of a trajectory in the vertical plane at V and a target at T directed in flight as indicated by the arrow B. Observing stations 03 and 04 are disposed in positions in rear of and forward of the gun position G respectively for the purpose of observing lateral deviations of the trajectory from the target.

Rays S3 originating at station 03 and indicating lines of sight intersecting the trajectory V from a point on the convexside of the trajectory,

show that certain of the lines of sight originating at a point on this side of the trajectory intersect the at two points. As would be expected, this situation is the same as the corresponding situation illustrated in Fig. l, i. e., the observer must visualize the target and intercept of the trajectory involved, in their true positions of range or depth before the true line of sight passing through the target can be established and, hence, the deviation of the trajectory from the target, because of the visual illusion existing in the inaccurate visualization of the objectives in true relative range from the observing point or station.

From station 04 rays S4 indicating typical lines of sight extending from a point on the concave side of the trajectory V in intersecting relation therewith, do, as would be expected from a comparison with the analagous situation of Fig. 1,

in regard to rays S2, intersect the trajectory V but once, and similarly illustrate the principle that lines of sight from an observing station on the concave side of the trajectory in its vertical projection intersect the trajectory but once and once only. In as much as the observer. at 04 can determine the line of sight S4 passing through the target T independent of the relative positions of range or depth of the trajectory and target it is, as in the case from O2 in Fig. 1, a simple matter to determine the deviation of the trajectory from the target.

From the description thus far of the specific example disclosed in Figs. 1 and 2 it is believed to be apparent that the observers at stations 02 and 04 will have no difficulty in determining the true vertical and laterial deviations respectively, of the trajectory from the target. Likewise it is believed to be apparent that true deviations or deviations of suflicient accuracy for proper fire control can never be obtained visually from stations 01 and 03 because of the slight probability of the observers establishing the true lines of sight intersecting the target from these points owing to the visual illusion obtained by deficient stereoscopic ability beyond ranges of short distances.

It will be noted that by utilizing two observers stationed on the concave side of the trajectory in proper disposition with respect to each other and the target that one observer located at a point relatively to the target and trajectory, such as station 02 in Fig. 1, may readily direct changes in the pointing of the gun or guns in elevation to cause the trajectory to be aligned with the target in vertical direction, range or elevation, and that the other observer relatively located at a point or station, such as 04 in Fig. 2, may readily direct changes in the pointing of the gun in azimuth or deflection to align the trajectory with the target in lateral direction. As above shown, the observers O2 and 04 are not hampered by visual illusion in determining the deviations of the trajectory from the target and consequently rapid and accurate adjustments may be made from points of observation positioned properly on the concave side of the trajectory for the trajectory is aligned with the target by the observers utilizing thetrajectory as a line which they cause to intersect the target in elevation, range, or vertical direction, and in lateral direction in much the same manner that the cross-hairs of a telescope are aligned with an object in its field of view or entirely independent of regard for the distance of the trajectory from the target in distance or depth from the observing stations.

To this point in the description conditions have been assumed for the purpose of illustration that would seldom be encountered in the field, for under combat conditions an aerial target is as apt to approach from one direction as it is from another, and a position defense to be prepared for contingency of approach from any direction must have a fire control system effective for fire through 360 of azimuth. Since a system of fire control based on the principles above disclosed requires two observers, one for lateral deviations and one for vertical deviations, disposed on the concave side of the trajectory, I have found that by disposing the observing stations relative to the gun position as schematically shown in Fig. 3 that it is always possible toselect two observing stations located on the concave side of the trajectory for determining the required lateral and vertical deviation of the trajectory from the target irrespective of the direction of the fiight of the target relative to the gun,

The observing stations 01 and 02 are located on the flanks or laterally of the position of the gun or guns viewed when the latter are pointed toward the top of the drawings, as they are in Fig. 1, and the observing stations 03, 04 are positioned at points in rear and forward of the guns respectively, as in Fig. 2. The stations may be located any suitable distance X from the position of the guns G, but best results have been obtained when distance X is approximately 10% of the maximum range of the guns being used. For facility in identification of the position of a target and apprising an operator at the gun position of which data to select from the data being transmitted by observers, the field of fire may be divided into quadrants here shown identified at I, II, III and IV respectively, or the quadrants may be enlarged to sectors appropriately overlapped for a well known reason and properly identified by any desired means.

Suitable channels of any conventional means of communication are established as indicated at R1, R2, R3 and R4 respectively, between the observing stations 01, O2, O4 and O4 and a central control station C, hereinafter described in detail in one embodiment.

With the observing stations located as shown in Fig. 3, it is always possible, irrespective of what quadrant or sector the target is flying over, or in I what direction it may be fiying in, for two of the observers to make observations of deviations of the trajectory from the target on the concave side of the trajectory in accordance with the above il lustrated principles; i. e., with one observer forward of the gun in the direction of fire, for observing lateral deviations, and one observer on the flank of the gun away from which the target is flying for observing vertical deviations.

All the observers may communicate the deviations they observe, by way of their respective channels of communication, to the central control station C where by means of selecting mecha- .nism in the central control, the operator thereof may select the deviations or corrections ordered rom the two observing stations located on the concave side of the trajectory and cause the selected deviations or corrections to be forwarded to the guns for application on the sights or to any other suitable point. Instead of having all the observers transmit deviations on all courses of all targets, the two observers necessary for control of fire in any particular quadrant or sector of the field of fire may be designated by the control station operator through the communication network, or otherwise informed, to transmit data for fire adjustment.

It is of course to be observed that in one posltion of a target that one observing station will be a forward observing station, whereas in another position of the target or the position of another target, the observing station will become a flank or rear station.

Mechanical apparatus is shown in Fig. 4 constituting one embodiment of a suitable central control for use at the station C. This control includes structure whereby an operator may select the data transmitted from any adjacent pair of observing stations for transmission to the sights of the gunsor other point.

Essentially the central control comprises a casing I for housing a transmission system of any suitable type generally designated at 2 and herein shown as of a selective gear train type, means 3 for transmitting observed deviations or correc tions ordered by the observers to the transmission system from each observing station 01, O2, 03, or 04 and transmission lines 4, 5 for transmitting data selected at the central control to the gun sights or other point.

The transmission 2 comprises a plurality of shafts 6, I, 8 and 9 mounted for axial and rotary movement, one forand operable from a corresponding observing station 01, O2, O3 and 04, respectively. Each of the shafts 6, I, 8 and 9 are axially shiftable from the neutral position shown in Fig. 4 to one of two operative positions, hereinafter more particularly pointed out, by shift levers ID, ll, I2 and [3 respectively. The shift levers are each pivoted intermediate their ends at M and provided on their inner ends with a forked portion engaged between the flanges of a collar l5 fixed to each of the axially movable shafts. The shafts B, I, 8 and 9 are rotatable either clockwise or counterclockwise by means 3 extending from each observing station 01, 02,. O3, or 04, and each shaft has fixed thereon a spur or friction gear l6, l7, IS, IS respectively. Two shafts 20, 2! are journaled within casing l for rotation and have end portions protruding from the casing as shown. The shaft 20 has the gears 23 and 38 afiixed thereon and shaft 2i has gears 30, 35 afiixed. Gear 23 fixed on shaft 20 comprises one of the gears of a train D of gears 22, 23, 24, 25 and 26, while gear 3!) fixed on shaft 21 is included in the train E of gears Z1, Z8, 29, 30 and 3!. Likewise gear 35 fixed on shaft 2| is included in a train F of gears 32, 33, 34, 35 and 35 while gear 38 fixed on shaft 2!) comprises one gear of the train G of gears 31. 38. 39. 49 and ll.

The means l, 5 for transmitting movement of shafts 2!). 2!, respectively, to the gun sights or other point are ident cal in construction and include a flexible cable, sheathed in a suitable protective cover, and secured at one terminal to a shaft 20 or 2! for rotation therewith. The means 4 transmit-s lateral deviations or corrections and means 5 transmits vertical deviations or correc tions. The free ends of the shafts compris ng means i and 5" may be directly secured to the lead screws 42, 43, respectively or other means for setting the sight S of a gun or guns, or to mechanism for indicating the observed deviations; but preferably, and as shown in Fig. 4 they are connected to one of the crown gears or comparable elements of differentials M and 45. respectively, for algebraically combining the motion transmitted thereby with arbitrary corrections or data from other sources.

When differentials M and 45 are employed in the system, the motion of the crown wheels or comparable elements as effected by means 4, 5 is algebraically combined with the motion of the other crown Wheelsor comparable elements of the differentials, as turned by the differential opcraters in accordance with or proportional to data they receive from any other source or sources so that the output of the differentials will be an algebraic combination of the corrections directed by the selected observers with the data from said other source or sources. In the embodiment shown in Fig. i a device 46 for computing lateral iii) and vertical leads is shown located in telephonic communication by lines 4'! and 48 with the stations of. the differentials 44 and G respectively, whereby lateral and vertical leads of the target may be computed by device 66 and transmitted by telephone to the stations of the differentials and there algebraically combined through the differentials by the operators with the datacoming through means 4 and 5 and transmitted through flexible cables 49, 50, respectively, rotatable in accordance with or proportional to the algebraic combination made by the differentials dd, 65 to the lead screws 42 and 63, respectively or other control elements of the sight S. The differentials may be provided with tally dials or other indicating mechanism to apprise the operators of the data transmitted to the sights by cables d9, 50.

The shafts '5, l, 8 and 9 of the transmission system 2 are operable from their corresponding observing stations 01, O2, O3, and 04 by similar means 3. Each means 3 may comprise a transmitter 5i and flexible cable 52 attached at one terminal to the transmitter for rotation thereby and at the other terminal to a shaft 6, 1, 8 or 9 as the case may be.

The transmitters 5! are provided with indicatrnechanisin graduated in suitable units, such for example as angular units, and are operable to rotate the flexible cables 52 either clockwise or counterclockwise an amount corresponding or proportional to the displacement of the index from the zero or normal position of the indicating mechanism of the transmitters.

A transmitter Fit may be located directly at each observing station, or in those situations where it is desirable to establish observing stations at distances beyond the practical range of employment of flexible cable the transmitter stations may be placed in communication with the observing stations by any conventional method. In the latter case the shafts 6, 1,8 and 9 may be directly operated at the control station C, if preferred, by provision of auxiliary means for rotating the same in accordance with the deviations communicated from the observing stations.

It will be observed that means 4, 5 for operating the sights of one gun only have been shown, simply for clarity of disclosure; but that in the practice of the invention a plurality of means a, 5 will extend from casing I in driven relation with the shafts 2D, 2! in order to simultaneously set the sights of any suitable number of guns.

In operation of the system, data will be con tinuously transmitted to the central control C from each observing station 01, O2, O3 and 04, or a designated pair of adjacent observing stations, by transmission means 3. The operator at the station of the central control C will select the lateral and vertical observed deviations or cor rections transmitted by the two observers on the concave side of the trajectory in accordance with the above principles and cause the same to be transmitted from central control C by proper manipulation of shifters H3, ll, l2 or l 3 through means 1 and 5 to differentials M and 45, respectively. For the purpose of illustration let it be assumed that a target To is in quadrant or sector I flying in the direction indicated, toward quadrant or sector II. To fulfill the conditions set forth above the observers at stations 04 and 02 would be selected by the central control operator at station C, or otherwise be designated to control fire on the target To. The observer at 04 would observe and adjust fire laterally or in azimuth and the observer at 02 would observe and adjust fire vertically or in elevation. Observer 04 is forward of the gun in the direction of fire and observer O2 is on the flank of the gun away from which the target is flying, therefore, both observers are on the concave side of the trajectory and will be enabled to function independently of any optical illusion. With observers 02 and 04 selected the operator of the central control at station C will operate the shifters H and !3 as follows: Shifter H will be moved to a position where gear ll operatively engages gear M to drive gear 30 and shaft 2!. Shifter 13 will be moved to a position where gear 49 will drive gears 22 and 23 and shaft 29. The lateral correction directed by the observer at station. 04 will be transmitted to differential 44 from shaft 20 through means 4 and there algebraically combined with a computed lateral lead from device it or with arbitrary data by the differential operator at that station. and the vertical correction directed by the observer at station 02 will be transmitted from. shaft 29 through means 5 to diiferential 45 where it will be algebraically combined with a computed vertical lead from device 46 or other appropriate data by the operator. The resultant lateral lead will be impressed on the sight S by cable ii? and lead screw 62 and the resultant vertical lead will be impressed on the sight by cable 50 and lead screw The sights will then be set to the proper lateral and vertical leads to cause the actual trajectory of the tracers to pass through the target.

In other situations it will be necessary to use 01 for vertical adjustments and 03 for lateral adjustments of fire. In this case the shifter it will be moved to cause gear it to drive gear of the gear train F and therethrough the shaft 25 by gear 35 to impress changes on the sight in elevation. The shifter l2 will be moved to cause gear I8 to drive the gear train G through gear 4! and hence shaft 25 and means 4 to impress changes on the sight in azimuth or deflection.

From the examples given it is believed that it is apparent that the shifters Hi to E3 inclusive, may be manipulated to cause any adjacent pair of stations to impress either lateral or vertical changes on the sight S, i. e., one of the pair of stations may change the sight setting in elevation or range while the other station of the pair may change the sight setting in deflection or azimuth, or vice versa.

Situations may at times make it advisable to use more than four observers in which case the transmission, if of the mechanical type, may be modified accordingly, or any other central con-- trol of the electrical or hydraulic type may be used or a special system designating the required two of any number of observers may be used. For the normal situation, however, the use of four observers will be sufficient to cover the entire field of fire of 360 azimuth and yet remain disposed as shown in Fig. 3.

Having now particularly described the invention and the present preferred embodiment of the same, what is claimed and desired to secure by United States Letters Patent is:

1. In a fire control system for pointing an ordnance piece at a moving target through a field of fire of 360 degrees azimuth and including a station for said ordnance piece and an adjacent control station, meansfor simultaneously observing the deviation of the trajectory relative to the target at two generally oppositely disposed flank stations and a forward and rear station, means for simultaneously transmitting the observed deviations to said control station and means at the latter station for selecting and transmitting deviations from a predetermined pair of flank and forward or rear observing means to a control element of said ordnance piece and for moving said element relatively to said ordnance piece.

2. In a fire control system for pointing ordnance at a target moving across afield of fire of 360 degrees in azimuth, a plurality of spaced observing stations located in positions around said ordnance, a control positioned at a station centrally of said observing stations comprising means for selecting data transmitted from a pair of observing stations and impressing it on said ordnance for controlling the pointing thereof, and means for transmitting data from each observing station to said control.

3. The structure of claim 2 wherein the means for impressing the data upon said ordnance comprises transmission lines extending from the central control to elements for controlling the pointing of the ordnance in azimuth and elevation.

4. The structure of claim 2 wherein the means for impressing the data upon said ordnance comprises transmission lines extending from the central control to elements for controlling the pointing of the ordnance in azimuth and elevation and said transmission .lines are each provided with means for algebraically combining the data transmitted from the central control with data from any other desirable source.

5. In a fire control system for pointing ordnance provided with sighting elements at a target moving across a field of fire of 360 degrees in azimuth, a plurality of spaced observing stations located in positions around said ordnance, a control positioned at a station centrally of said observing stations, means for transmitting data from each observing station to the central control, transmission lines extending from the central control to members on the sights for setting the latter in azimuth or deflection and range or elevation and means included in said central control for selecting data transmitted from a pair of the plurality of observing stations for impression upon said transmission lines.

6. In a fire control system for pointing ordnance provided with sighting elements at a target moving across a field of fire of 360 degrees in azimuth, a plurality of spaced observing stations'located in positions around said ordnance, a control positioned at a station centrally of said observing stations, means for transmitting data from each observing station to the central control, transmission lines extending from the central control to members on the sights for setting the latter in azimuth or deflection and range or elevation, means included in said central control for selecting data transmitted from a pair of the plurality of observing stations for impression upon said transmission lines and means provided in each transmission line for algebraically combining the data transmitted from the central control with data from any other desirable source.

'7. In a fire control system for pointing a gun adapted to fire a projectile with a visible trajectory at a moving target, a station for said gun, a control station adjacent the gun, a flank and forward observing station so disposed with respect to the trajectory that vertical and lateral deviations thereof with respect to the target may be observed from the concave side of the trajectory, means for transmitting observed deviations from said observing stations to the control station, transmission lines extending from the control station to elements of the gun for controlling the pointing thereof and means included in said central control for selecting data received thereby for transmission over said lines.

FREDERICK R. CHAMBERLAIN, JR. 

